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Pittsburgh Epidemiologists Say Breakthrough COVID-19 Cases Were Expected, But Vaccines Are Still Safest

Nawaf Albarakati, 17, of Narberth, Pa., reacts as he receives a Pfizer COVID-19 vaccination from registered nurse Alicia Jimenez at a Montgomery County, Pa., Office of Public Health vaccination clinic at the King of Prussia Mall, Tuesday, May 11, 2021, in King of Prussia., Pa.
Matt Slocum
/
AP
Nawaf Albarakati, 17, of Narberth, Pa., reacts as he receives a Pfizer COVID-19 vaccination from registered nurse Alicia Jimenez at a Montgomery County, Pa., Office of Public Health vaccination clinic at the King of Prussia Mall, Tuesday, May 11, 2021, in King of Prussia., Pa.

Breakthrough cases occur when fully vaccinated individuals contract COVID-19. Health experts say breakthrough cases were always anticipated because vaccine efficacy isn’t 100%.

“The key point about the breakthrough cases is that they are mild relative to cases that occur in the unvaccinated population,” said Dr. Lee Harrison, M.D., professor of epidemiology and infectious diseases at the University of Pittsburgh Graduate School of Public Health.

Mild breakthrough cases occur because the goal of vaccines was to prevent serious infections resulting in hospitalizations and deaths, said Dr. David Dausey, executive vice president and provost of Duquesne University and epidemiologist by trade.

“If more people were vaccinated, we would not be seeing the outbreaks and the cases that we're seeing right now,” Dr. Dausey said.

Allegheny County is seeing a “substantial” rate of transmission, with 58.5 COVID-19 cases per 100,000 people. The change of CDC designation comes as the contagious delta variant spreads around the country. Harrison said the deadly aspect of the spread is preventable through vaccines.

“The breakthrough cases make a fabulous case for getting vaccinated, because what we're seeing is that the patients who are being admitted to the hospital and the patients who are dying in general are unvaccinated individuals,” Harrison said. “The bottom line is that vaccination protects against hospitalization and death.”

CDC guidelines still require self-isolation for individuals who contract COVID-19, regardless of their vaccination status.